Modeling of Diels-Alder reversible network formation under diffusion-controlled conditions for the construction of cure diagrams

Description

In recent years, significant attention has been devoted to the study of thermoreversible networks based on Diels-Alder (DA) bonding for their potential as self-healing materials. Two competing equilibria result from the DA reaction, involving endo- and exo- cycloadducts, with covalent bond formation favored at low temperatures and their opening preferred at higher temperatures. Apart from granting self-healing abilities, these dynamic bonds enhance material lifetime, stability, reliability and sustainability, but also improve recyclability, reprocessability, and reshapeability compared to traditional network-forming materials. These enhanced properties make these materials suitable for many applications, especially those requiring robust thermomechanical properties. Such applications imply the necessity of a (partially) vitrified network with a sufficiently high glass transition temperature (Tg ). This will inevitably affect their self-healing, as both forward and retro-DA reaction rates may be impacted by the limited mobility.
In this work, the impact of vitrification on DA reaction kinetics is investigated for a reversible thermosetting network based on a furan-maleimide chemistry. First, the feasibility of self-healing in diffusion-controlled conditions is proven. Secondly, a novel mechanistic model describing the system in both kinetically and diffusion-controlled conditions is proposed. Optimization of the kinetic, thermodynamic, and diffusion parameters was done using calorimetric data and Tg evolutions. These parameters allowed the construction of Time-Temperature-Transformation and Continuous-Heating-Transformation. Their unique shapes, largely different from classical irreversible thermosets, were experimentally confirmed by thermo(mechanical) analysis. This insight is particularly relevant for the design and processing of these materials, emphasizing their potential in self-healing applications.

Periode	24 jun 2024 → 26 jun 2024
Evenementstitel	9th International Conference on Self-Healing Materials: ICSHM2024
Evenementstype	Conference
Locatie	Madrid, Spain
Mate van erkenning	International